// run-pass // // At one time, the `==` operator (and other binary operators) did not // support subtyping during type checking, and would therefore require // LHS and RHS to be exactly identical--i.e. to have the same lifetimes. // // This was fixed in 1a7fb7dc78439a704f024609ce3dc0beb1386552. #[derive(Copy, Clone)] struct Input<'a> { foo: &'a u32 } impl <'a> std::cmp::PartialEq> for Input<'a> { fn eq(&self, other: &Input<'a>) -> bool { self.foo == other.foo } fn ne(&self, other: &Input<'a>) -> bool { self.foo != other.foo } } fn check_equal<'a, 'b>(x: Input<'a>, y: Input<'b>) -> bool { // Type checking error due to 'a != 'b prior to 1a7fb7dc78 x == y } fn main() { let i = 1u32; let j = 1u32; let k = 2u32; let input_i = Input { foo: &i }; let input_j = Input { foo: &j }; let input_k = Input { foo: &k }; assert!(check_equal(input_i, input_i)); assert!(check_equal(input_i, input_j)); assert!(!check_equal(input_i, input_k)); }